US2262829A - Brake - Google Patents

Description

Nov. 18, 1941. D. T. BROck BRAKE Filed April 18, 1959 2 Sheets-Shget 1 INVENTOR. jams Tesorz J5r2oc| BY ATTORNEY.

Patented Nov. 18, 194 1 UNITED STATES PATENT OFFICE BRAKE Denis Tabor Brock, London, England, assignor to Company Limited, Lon- Automotive Products don, England Application April 18, 1939, Serial No. 268,593 In Great Britain April 23, 1938 11 Claims.

being automatically balanced one against the other with a view to providing a substantially constant ratio between the brake-applying forces on the various wheels of the vehicle.

In a vehicle braking system having a set of brakes which is actuated by pressure liquid fed through pipe lines from a master cylinder unit having operating means, according to the present invention another set of brakes is connected by a mechanical rigging to that part of the master cylinder unit and operating means which receives the reaction force serving to place the master cylinder unit and operating means in equilibrium, so that forces bearing a predetermined ratio are simultaneously applied by the operating means to the master cylinder unit and to' the brake rigging respectively.

Thus, there is provided according to the invention a vehicle braking system having a set of brakes which is actuated by pressure liquid fed through pipe lines from a master cylinder unit having operating means, and also another set of brakes which is actuated by a mechanical rigging, a movable part of the latter being arranged to serve as an anchorage for the master cylinder unit or its operating means so that movement of said operating means applies to both sets of brakes simultaneously actuating forces which bear a predetermined ratio to one another. In one arrangement a common operating means is connected by a mechanical forcedividing device, with the rigging and the master cylinder unit respectively wherebyboth sets of brakes are applied simultaneously by forces bearing a predetermined ratio. Alternatively, the master cylinder unit itself may be mounted upon a movable portion of the mechanical rigging so that when the operating means is moved it creates pressure in the master cylinder unit and at the same time applies through the mas ter cylinder unit a force to the mechanical rigging subsantially proportional to the liquid pressure generated in the master cylinder unit.

' Where the master cylinder unit is carried r18- idly upon the vehicle, the operating means of said unit preferably comprises a lever pivotally mounted upon an anchorage which has freedom of movement in a direction parallel with the force applied to the master cylinder unit, the lever being also connected with the mechanical rigging to apply a force thereto in a direction also substantially parallel with. said freedom of movement. Thus, the anchorage may comprise a link which is pivoted to a fixed support at one end and carries the lever pivotally atthe other, the anchorage conveniently being centered by a resilient device comprising a pair of opposed coiled compression springs arranged coaxially upon a plunger having a projection between said springs, and'normally disposed in register with a fixed stop member, the arrangement being such that movement of the anchorage from its normal position causes one of the springs to be compressed by the stop member, and thus to cal rigging it may conveniently be carried upon the free end of an angularly movable link pivoted to the vehicle, the brake rigging being connected either directly with the master cylinder unit or to an extension of the supporting link.

The invention is illustrated in the accompanying diagrammatic drawings in which:

Figure l is a side elevation of a braking system for a four-wheeled vehicle, the front wheel brakes being actuated by pressure liquid and the rear brakes being applied by a mechanical rigins;

Figure 2 is an enlarged sectional elevation show the construction of the resilient centralizer device included in Figure l;

Figure 3 is a part-sectional elevation showing a modified form of brake-applying means; and

Figure 4 is a similar view of another modification. v i

The braking system shown in Figures 1 and 2 comprises a master cylinder unit lll'which is rigidly fixed by means of a bracket H to the chassis of thevehicle indicated at l2, said master cylinder unit being arranged to deliver pressure liquidthrough pipe lines l3 and M to front wheel brakes shown diagrammatically, at I! and 16 respectively. A breathing pipe I! is connect ed in the usual manner with a reservoir ll con- 5 22 secured to a link 23, which latter is pivoted to the chassis l2 by means of a bolt 24. At the point 25 where the pedal lever 2| would normally be pivotally'mounted upon the chassis said lever is in the present instance free to move horizontally, and is connected by a U-shapedfltting 28 with a tension rod 21 forming part of a mechanical rigging for applying the rear brakes of the vehicle. These brakes are indicated to a reduced scale at 28 and 29 and the linkage operatin the transverse tension rods 3| -and-32 are always equalized. An arm 35 pivoted upon a fixed stud 38 is operatively connected with the front end of the secondary tension rod 34 by means of a U-shaped fitting 31, while a pin 38 provided .intermediate the ends of the arm 35 cooperates with a slider 39 provided upon the rear end of the tension member 21' in such a way that the arm 35 can move forwardly without shifting said tension member 21. On the other hand forward movement of the tension member 21 is imparted to the arm 35-and causes the rear brakes 28 and 29 to be applied.

The vehicle is fitted with an auxiliary hand' lever 40 for use in emergency and parking, this lever being pivoted to the chassis at 4| and having at its lower extremity a pin 42 which is connected by a slotted fitting 43 with an auxiliary tension rod 44. It will be seen that the rear end of the latter is also pivoted to the upper part of the arm 35, so that when the hand lever 40 is moved rearwardly a pull is exerted upon the tension rod 44 consequently applying the brakes 28 and 29. Owing to the provision of the'slotted fitting 39 this movement is not imparted to. the pedal lever 2|, while in a similar manner the hand lever 40 is not affected when the pedal lever 2| is actuated, this being on account of the slotted fitting 43 which permits the auxiliary tension rod 44 to move rearwardly with the arm 35 without shifting the hand lever 4|i. The push rod i9 is formed with a shoulder 13 which wevents the whole movement of the pedal lever 2| from being imparted to the master, unit it should the hydraulic system fail, the shoulder 13 being arranged to abut against a guide member 14 when the normal maximum movement of the rod' 9 has taken place. For a similar purpose the tension member 21 passes through an abutment stop member 48. A pair of relatively weak coiled compression springs 52 and 53 respectively are threaded over the plunger member 48 and co-- operate at their inner ends with the collars 59 and 5|. The outer end of the spring 52 bears against a head 54 which is drilled to fit over the bolt 22,

while the outer end of the spring 53 is similarly supported by a nut 55. The two springs 52 and 53 normally center the plunger member turn spring 58 is provided, one end being anchored,

48 by forcing the collars 50 and 5| against the 'stop member 48, and when said plunger member 48 is moved axially one or, other of the springs becomes compressed and so exerts a force which again centralizes the plunger member 48- at the first opportunity. 'A pedal lever reto the chassis l2 at 51, while the other is hooked through the forked member 28. v

When force is applied to the operating means of the master cylinder unit Hi, i. e. to the pedal lever 2|, a thrust is produced in the push rod l9 and at the same time a tension occurs in the tension rod 21. The fulcrum of the lever 2| is, therefore, indeterminate, and a balance is automatically produced between, on the one hand, the thrust in the push rod l9 tending to apply the'f'ront wheel brakes l5 and I8, and on the other'hand the tension in the tension rod 21 serving to apply the rear wheel brakes 28 and 29 through the mechanical rigging comprising members 21, 35, 34, 33, 3| and 32. The reaction.

upon the pedal lever 2| which occurs owing to the production of a thrust in the push rod I9 is.

thus used to secure a braking force for the rear wheel brakes 28 and 29, which force naturally bears a predetermined ratio with'respect to the force exerted in the push rod IS with the result that when the system is properly adjusted a predetermined ratio is maintained between the applying forces for the front wheel and rear ,wheel brakes, irrespective of the force which is imparted to the pedal lever 2|. It will be appreciated, of course, that th lever 40 serves to actuate only the rear brakes- 28 and 29.

The improved result can be obtained with other arrangements and two modifications are shown in Figures 3 and 4 respectively. In Figure '3 the master cylinder unit I9 is not mounted rigidly upon the chassis |2 but is attached pivotally at 59 to the lower end of a lever 80, itself pivoted intermediate its length to the chassis |2 at 8|.

15 which, in the event of the rear-brakes becoming inoperative through breakage, is engaged by a collar 18 fixed on the tension member21.

With a view to stabilizing the mechanical parts of the braking system when the latter is inoperative, a resilient .centralizer device 'is prefer- .ably included, and one form is indicated generally at-45 in Figure '1, this being operatively connected between the bolt 22 and the chassis |2 in such a manner that the link 23 is always 'urged towards its central vertical position. The

construction of the device is shown more clearly in Figure 2, from which it will be seen that it comprises anv "annular stop member 48 which isformed with a plate 41 secured to the chassis l2. A plunger 48 having a central projection 49 in the form' of a radial flange is slidably mounted in The upper end of the lever 89 is connected at 82 with a tension rod 83 forming part of the rigging of a mechanical brake and corresponding, for example, to the'tension rod 21 in Figure l. The usual piston 84 of the master cylinder unit I! is pivoted at 85 to the lower end of the pedal lever,

2|, which latter in this instance is pivoted at 88 to the chassis l2. Afiexible pipe 81 leads to the front wheel brakes of the vehicle, which brakes i ply the front wheel brakes. The liquidpressure at the same time acts upon the end wall of said cylinder and instead of this reaction force being resisted by the chassis, as would occur if the master cylinder unit were rigidly attached in V ly. Should the hydraulic system fail, for ex-.

ample due to a leakage in the pipe 61, the lever 60 will remain stationary during the first part of the movement of the pedal lever 2| as no pressure will be generated in the master cylinder unit Hi. When the pedal lever 2| has moved through a fraction of its maximum travel however, the projection 68 will abut against the stop 69 so that further movement of said pedal lever will be directly imparted to the lever 60 and will serve for applying the rear wheel brakes.

A somewhat similar arrangement is shown in Figure 4, but in this instance the tension rod 63 is connected directly with the master cylinder unit III, the piston 64 of which is actuated by a curved arm secured to a pedal lever spindle II. The opposite end of the master cylinder unit is supported by a link 12 pivoted to the chassis l2 at El and to the master cylinder unit l0 at 59.

It will be appreciated that the constructional details of the arrangements according to the invention may be adapted to suit requirements and that the member which,is connected to operate the mechanical brake rigging may be mounted in a number of ways to permit the desired force transference. Thus, for example, in the case of the master cylinder the latter can be mounted upon slides or could be carried by a cradle which is supported through the medium of a number of links constituting a parallelogram. Further, some at least of the vehicle brakes may be provided with alternative fluid pressureand me-' chanical applying means, and in such an arrangement all the brakes may have hydraulic wheel cylinders connected by pipe lines with the master cylinder unit, the mechanical operating means of said brakes being coupled to the brake 4 rigging as hereinbefore described.

prising an anchorage, a lever pivoted on said anchorage, wherein the anchorage comprises a fixed support and a link which is pivoted to said flxed support at one end and carries the lever pivotally at the other, and wherein the lever is also connected with the mechanical rigging to apply a force thereto.

3. A braking system for a vehicle comprising one set of brakes having fluid actuation, another set of brakes having mechanical actuation, a master cylinder unit having operating means, wherein the operating means comprises a lever, an anchorage, said lever being pivotally mounted upon said anchorage, and a resilient device which centers said anchorage when the brakes are inoperative.

4. A braking system for a vehicle comprising one set of brakes having fluid actuation, another set of brakes having mechanical actuation, a

master cylinder unit having operating means, wherein the operating means comprises a lever, an anchorage, said lever being pivotally mounted upon said anchorage, and a resilient device which centers said anchorage when the brakes are inoperative, said resilient device comprising a pair of opposed coiled compression springs arrangedcoaxially upon a plunger having a projection between said springs and normallydisposed in registration with afixed stop member, the arrangement being such that movement of the anchorage from its normal position causes one of the springs to be compressed by the stop member, and thus to urge the plunger to its normal position. r

5. A vehicle braking system having a set of brakes, a master, cylinder, operating means for said master cylinder which feeds fluid pressure through pipe lines to actuate said set of brakes, another set of,brakes, a mechanical rigging for actuating said last named set of brakes, and an angularly movable lever pivoted to the vehicle which carries said master cylinder unit upon its free end and which serves as an anchorage for said master cylinder unit or its operating means so that movement of said operating means applies to both sets of brakes simultaneously, actuating forces which bear a predetermined ratio to one another.

6. A vehicle braking system having a set of brakes, a master cylinder, operating means for said master cylinder which feeds fluid pressure through pipe lines to actuatesaid set of brakes,

another set of brakes, a mechanical rigging for actuating said last named set of brakes, and an angularly movable lever pivoted intermediate its length to the vehicle which lever carries said master cylinder. unit upon its free end and in which the free end opposite its attachment to having a master cylinder unit carried rigidly upon said vehicle, wherein they operating means of said unit comprises a lever which has freedom of movement in a direction substantially parallel with the force applied to the master cylinder unit, and an anchorage on which said lever is pivotally mounted and wherein there is' a me- .chanical rigging connected to the lever -to receive upon said vehicle, having operating means comsaid master cylinder unit is connected with said mechanical brake rigging, said angularly movable lever also serving as an anchorage for said master cylinder unit or its operating means so that movement of said operating means applies to both sets of brakes simultaneously, actuating forces which bear a predetermined ratio to one another.

"I. A braking systemfor a vehicle having one set of brakes actuated by fluid pressure and an.

other set of brakes, and rigging for actuating said other. set of brakes mechanically and hav- -ing a master cylinder unit carried rigidly upon said vehicle, wherein there is provided an operating means for applying force to the master cylinder and to said rigging, wherein the operating means for said unit comprises a leverwhich rigging by the operating means should a failure occur in the fluid pressure brakes, and an anchorage on which said lever is pivotally mounted and wherein there is a mechanical rigging connected to thelever to receive force from the lever in a direction substantially parallel with said freedom of movement.

8. A vehicle braking system comprising an applying lever, a hydraulic master cylinder unit, a brake associated with the said master cylinder unit, a mechanical brake rigging connected to said applying lever by said master cylinder unit, a brake associated with the said mechanical brake rigging, and .an angularly movable link member pivotally secured to the cylinder part of the master cylinder unit and attaching said unit to the vehicle.

9. A vehicle braking system comprising an applying lever, a hydraulic master cylinder unit, an angularly movable link member pivotally secured to the cylinder part of the master cy1in-' der unit and attaching said unit to the vehicle,

and a mechanical] brake rigging connected to' said applying lever by said master cylinder unit, said master cylinder unit being free to move axially so that part 01' the work from said lever aacaaae when the brakes are applied isabsorbed by the master cylinder unit to create liquid pressure for applying the brakes and part of the work from said lever is absorbed by said mechanical brake rigging. V

10. A vehicle braking system comprising an applying lever, a hydraulic master cylinder unit, a mechanical brake rigging connected tosaid applying lever through the medium of said master cylinder unit, a piston associated with said master cylinder unit adapted to receive a thrust force from the applying lever to create liquid pressure, and a supporting lever carrying the cylinder portion of said master cylinder unit, said supporting lever being pivoted intermediate its length to the vehicle and the free end of the supporting lever opposite to its attachment to the master cylinder unit being connected with the mechanical brake rigging,

11. A vehicle braking system comprising a first set of brakes, means including amaster cylinder having fluid therein for actuating said flrstset of brakes, a second set of brakes, mechanical rigging .for actuating said second set'of brakes, means for putting the fluid in the master cylinder under pressure, said last named means being anchored on a movable part of the mechanical rigging so that movement of said last named means applies to both sets of brakes simultaneously actuating forces which bear'.a predetermined ratio to one another.

DENIS TABOR BROCK.

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